That spool caught my eye straight away. I suppose the workers must use it to get in or out of the basin when drained as the usual ladders will nit fully support the weight without water assisting. Best guess! Kind of sad seeing the water drained away…

I just assumed local ne’er do wells threw the spool in – I like your theory better. And it is sad to see the water drained away, especially since we don’t exactly have a lot of extra water around here!